"""Abstraksi penyimpanan: sqlite (default) atau MariaDB/MySQL (PyMySQL).

Pilih backend via config `VEX_DB_BACKEND` (env `.env`). Kedua backend memakai
skema `voters` yang sama; query berbagi sintaks ditulis dengan placeholder
`%s` yang diterjemahkan ke `?` untuk sqlite. Dashboard read-only (V10).
"""

import sqlite3

from config import (DB_BACKEND, DB_HOST, DB_NAME, DB_PASS, DB_PORT, DB_PATH,
                    DB_USER)

# Skema voters — sama untuk kedua backend (I.db)
_COLS = (
    'owner VARCHAR(13) PRIMARY KEY, '
    'weight TEXT NOT NULL, '
    'staked DOUBLE NOT NULL, '
    'scanned_at TEXT NOT NULL, '
    'last_vote TEXT'
)
_SCHEMA = f'CREATE TABLE voters ({_COLS})'
_SCHEMA_IF_NOT_EXISTS = f'CREATE TABLE IF NOT EXISTS voters ({_COLS})'


def _translate(sql):
    """sqlite pakai `?`; mysql pakai `%s`. Ubah `%s` → `?` untuk sqlite."""
    return sql.replace('%s', '?') if DB_BACKEND == 'sqlite' else sql


def connect():
    """Buka koneksi backend. sqlite: WAL agar pembaca tak terblokir."""
    if DB_BACKEND == 'sqlite':
        conn = sqlite3.connect(DB_PATH)
        conn.execute('PRAGMA journal_mode=WAL')
        return conn
    if DB_BACKEND == 'mysql':
        import pymysql
        return pymysql.connect(
            host=DB_HOST, port=DB_PORT, user=DB_USER, password=DB_PASS,
            database=DB_NAME, charset='utf8mb4',
        )
    raise ValueError(f'VEX_DB_BACKEND tak dikenal: {DB_BACKEND!r}')


def query(sql, params=()):
    """Jalankan SELECT → daftar baris (tuple), koneksi dibuka-tutup tiap panggil."""
    conn = connect()
    try:
        cur = conn.cursor()
        cur.execute(_translate(sql), params)
        return list(cur.fetchall())  # sqlite→list, PyMySQL→tuple: seragamkan
    finally:
        conn.close()


def queryone(sql, params=()):
    """Jalankan SELECT → baris pertama (tuple) atau None."""
    conn = connect()
    try:
        cur = conn.cursor()
        cur.execute(_translate(sql), params)
        return cur.fetchone()
    finally:
        conn.close()


def replace_snapshot(rows, scanned_at):
    """V7: ganti snapshot voters tiap skan (⊥ history/append).

    sqlite: DROP+CREATE+INSERT (WAL melindungi pembaca).
    mysql: CREATE IF NOT EXISTS + DELETE + INSERT dalam satu transaksi
    → MVCC memberi pembaca snapshot konsisten (⊥ torn read saat ganti harian).
    """
    tuples = [(r['owner'], r['weight'], r['staked'], scanned_at, r.get('last_vote'))
              for r in rows]
    conn = connect()
    try:
        cur = conn.cursor()
        if DB_BACKEND == 'sqlite':
            cur.execute('DROP TABLE IF EXISTS voters')
            cur.execute(_SCHEMA)
            cur.executemany(
                'INSERT INTO voters (owner, weight, staked, scanned_at, last_vote) '
                'VALUES (?, ?, ?, ?, ?)',
                tuples,
            )
        else:
            cur.execute(_SCHEMA_IF_NOT_EXISTS)
            cur.execute('DELETE FROM voters')
            cur.executemany(
                'INSERT INTO voters (owner, weight, staked, scanned_at, last_vote) '
                'VALUES (%s, %s, %s, %s, %s)',
                tuples,
            )
        conn.commit()
    finally:
        conn.close()


# ——————————————————————————————————————————————————————————————————————
# Riwayat distribusi profit-share (V19..V27). Tabel append — tiap transfer
# & tiap run tercatat permanen (⊥ hapus). Skema sama untuk kedua backend,
# beda hanya klausa primary key autoincrement.
# ——————————————————————————————————————————————————————————————————————

_RUN_COLS = (
    'run_date TEXT NOT NULL, '
    'balance_start DOUBLE NOT NULL, '
    'total_voters INTEGER NOT NULL, '
    'total_staked DOUBLE NOT NULL, '
    'total_sent DOUBLE NOT NULL, '
    'status TEXT NOT NULL, '
    'created_at TEXT NOT NULL'
)
_PAY_COLS = (
    'run_id INTEGER NOT NULL, '
    'owner VARCHAR(13) NOT NULL, '
    'amount DOUBLE NOT NULL, '
    'txid TEXT, '
    'status TEXT NOT NULL, '
    'error TEXT, '
    'created_at TEXT NOT NULL, '
    'updated_at TEXT NOT NULL'
)

_RUN_DDL_SQLITE = f'CREATE TABLE IF NOT EXISTS distribute_runs (run_id INTEGER PRIMARY KEY AUTOINCREMENT, {_RUN_COLS})'
_PAY_DDL_SQLITE = f'CREATE TABLE IF NOT EXISTS distribute_payments (payment_id INTEGER PRIMARY KEY AUTOINCREMENT, {_PAY_COLS})'
_RUN_DDL_MYSQL = f'CREATE TABLE IF NOT EXISTS distribute_runs (run_id INT AUTO_INCREMENT PRIMARY KEY, {_RUN_COLS})'
_PAY_DDL_MYSQL = f'CREATE TABLE IF NOT EXISTS distribute_payments (payment_id INT AUTO_INCREMENT PRIMARY KEY, {_PAY_COLS})'


def ensure_distribute_schema():
    """Buat tabel riwayat distribusi bila belum ada (idempoten, kedua backend)."""
    conn = connect()
    try:
        cur = conn.cursor()
        if DB_BACKEND == 'sqlite':
            cur.execute(_RUN_DDL_SQLITE)
            cur.execute(_PAY_DDL_SQLITE)
        else:
            cur.execute(_RUN_DDL_MYSQL)
            cur.execute(_PAY_DDL_MYSQL)
        _drop_pay_memo(cur)
        conn.commit()
    finally:
        conn.close()


def _drop_pay_memo(cur):
    """Migrasi: buang kolom memo lama dari distribute_payments (idempoten).

    Kolom `memo` pernah disimpan (V23) lalu dihapus — DB produksi yang sudah
    punya kolom perlu di-alter; DB baru langsung tanpa kolom.
    """
    if DB_BACKEND == 'sqlite':
        cur.execute(
            "SELECT name FROM pragma_table_info('distribute_payments')")
        cols = {row[0] for row in cur.fetchall()}
    else:
        cur.execute(
            "SELECT COLUMN_NAME FROM information_schema.COLUMNS "
            "WHERE TABLE_SCHEMA = DATABASE() "
            "  AND TABLE_NAME = 'distribute_payments'")
        cols = {row[0] for row in cur.fetchall()}
    if 'memo' in cols:
        cur.execute(_translate('ALTER TABLE distribute_payments DROP COLUMN memo'))


def record_run(run_date, balance_start, total_voters, total_staked,
               total_sent, status, created_at):
    """Insert baris `distribute_runs`, kembalikan run_id."""
    ensure_distribute_schema()
    conn = connect()
    try:
        cur = conn.cursor()
        cur.execute(_translate(
            'INSERT INTO distribute_runs '
            '(run_date, balance_start, total_voters, total_staked, total_sent, '
            ' status, created_at) VALUES (%s, %s, %s, %s, %s, %s, %s)'),
            (run_date, balance_start, total_voters, total_staked, total_sent,
             status, created_at))
        conn.commit()
        return cur.lastrowid
    finally:
        conn.close()


def record_payment(run_id, owner, amount, status, created_at,
                   txid=None, error=None):
    """Insert baris `distribute_payments` → payment_id."""
    ensure_distribute_schema()
    conn = connect()
    try:
        cur = conn.cursor()
        cur.execute(_translate(
            'INSERT INTO distribute_payments '
            '(run_id, owner, amount, txid, status, error, created_at, '
            ' updated_at) VALUES (%s, %s, %s, %s, %s, %s, %s, %s)'),
            (run_id, owner, amount, txid, status, error, created_at,
             created_at))
        conn.commit()
        return cur.lastrowid
    finally:
        conn.close()


def update_payment_status(payment_id, status, txid=None, error=None, updated_at=None):
    """Perbarui status satu transfer (V21): pending → sent|failed."""
    from datetime import datetime
    if updated_at is None:
        updated_at = datetime.now().isoformat(timespec='seconds')
    conn = connect()
    try:
        cur = conn.cursor()
        cur.execute(_translate(
            'UPDATE distribute_payments SET status = %s, txid = %s, '
            'error = %s, updated_at = %s WHERE payment_id = %s'),
            (status, txid, error, updated_at, payment_id))
        conn.commit()
    finally:
        conn.close()


def update_run_status(run_id, status, total_sent):
    """Tutup run: status ok|partial + total terkirim nyata."""
    conn = connect()
    try:
        cur = conn.cursor()
        cur.execute(_translate(
            'UPDATE distribute_runs SET status = %s, total_sent = %s '
            'WHERE run_id = %s'),
            (status, total_sent, run_id))
        conn.commit()
    finally:
        conn.close()


def list_runs():
    """Ringkasan run distribusi, terbaru dulu."""
    ensure_distribute_schema()
    return query(
        'SELECT run_id, run_date, balance_start, total_voters, total_staked, '
        '       total_sent, status, created_at '
        'FROM distribute_runs ORDER BY run_id DESC')


def list_payments(run_id=None):
    """Transfer per-pemilih, terbaru dulu; opsional filter satu run."""
    ensure_distribute_schema()
    sql = ('SELECT payment_id, run_id, owner, amount, txid, status, error, '
           '       created_at, updated_at FROM distribute_payments')
    params = ()
    if run_id is not None:
        sql += ' WHERE run_id = %s'
        params = (run_id,)
    sql += ' ORDER BY payment_id DESC'
    return query(sql, params)